British Prime Minister David Cameron has said Afghanistan and Nigeria have taken "remarkable steps forward" on corruption, after calling the countries "fantastically corrupt."

Addressing members of Parliament on May 11, Cameron said the countries' leaders were "battling hard against very corrupt systems."

Cameron's original comments about the two countries came while he was speaking at a London reception on May 10.

"We've got some leaders of some fantastically corrupt countries coming to Britain -- Nigeria and Afghanistan, possibly the two most corrupt countries in the world," Cameron said, referring to a May 12 anticorruption summit in London.

Reacting to the comments, Afghan President Ashraf Ghani's spokesman, Zafar Hashemi, said, “It is our commitment -- not only to the Afghan people but [also] to the international community -- that we are serious about fighting corruption in Afghanistan."

Afghanistan is at No. 166, second from last, in Transparency International's latest Corruption Perceptions Index, an annual ranking of countries. Nigeria is ranked 136th.